21923429491 has 2 divisors, whose sum is σ = 21923429492. Its totient is φ = 21923429490.

The previous prime is 21923429447. The next prime is 21923429533. The reversal of 21923429491 is 19492432912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21923429491 is a prime.

It is not a weakly prime, because it can be changed into another prime (21923429441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10961714745 + 10961714746.

It is an arithmetic number, because the mean of its divisors is an integer number (10961714746).

Almost surely, 2^21923429491 is an apocalyptic number.

21923429491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21923429491 is an equidigital number, since it uses as much as digits as its factorization.

21923429491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 46.

The spelling of 21923429491 in words is "twenty-one billion, nine hundred twenty-three million, four hundred twenty-nine thousand, four hundred ninety-one".